Many fixes

content/html/en/blog/Haskell-the-Hard-Way.md

@@ -226,11 +226,6 @@ A major part of this tutorial will explain why.
 In Haskell, there is a `main` function and every object has a type.
 The type of `main` is `IO ()`.
 This means, `main` will cause side effects.
-`IO` is a ... . 
-Wait! No! I won't say it now!
-I am afraid to terrify you.
-You might run away crying.
-For now, I won't talk about what `IO` really is.
 
 Just remember that Haskell can look a lot like other imperative languages.
 
@@ -702,7 +697,7 @@ square'' x = (^2) x
 </code>
 </div>
 We can remove `x` in the left and right side!
-It's called currying.
+It's called η-reduction.
 
 <div class="codehighlight">
 <code class="haskell">
@@ -812,7 +807,7 @@ int evenSum(int *list) {
 int accumSum(int n, int *list) {
     int x;
     int *xs;
-    if (*list == NULL) { // if the list is empty
+    if (*list == 0) { // if the list is empty
         return n;
     } else {
         x = list[0]; // let x be the first element of the list
@@ -990,7 +985,9 @@ evenSum l = accumSum 0 l
 </code>
 </div>
 What is pattern matching? 
-Use value instead of general parameter name.
+Use value instead of general parameter name[^021301].
+
+[^021301]: For the brave, a more complete explanation of pattern matching can be found [here](http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html).
 
 Instead of saying: `foo l = if l == [] then <x> else <y>`
 You simply state:  
@@ -1036,7 +1033,7 @@ main = print $ evenSum [1..10]
 
 <hr/><a href="code/02_Hard_Part/14_Functions.lhs" class="cut">02_Hard_Part/<strong>14_Functions.lhs</strong></a>
 
-In Haskell you can simplify function definition by curry them.
+In Haskell you can simplify function definition by η-reducing them.
 For example,  instead of writing:
 
 <code class="haskell">
@@ -1221,7 +1218,7 @@ The `(.)` function correspond to the mathematical composition.
 (f . g . h) x ⇔  f ( g (h x))
 </code>
 
-We can take advantage of this operator to curry a bit more our function:
+We can take advantage of this operator to η-reduce our function:
 
 <code class="haskell">
 -- Version 9
@@ -2585,7 +2582,7 @@ let (y,w') = action x w in
 
 Even if for some line the first `x` argument isn't needed.
 The output type is a couple, `(answer, newWorldValue)`.
-Each function `f` must have a type of kind:
+Each function `f` must have a type similar to:
 
 <code class="haskell">
 f :: World -> (a,World)
@@ -2619,7 +2616,7 @@ And of course `actionN w :: (World) -> (a,World)`.
  > 
  > ~~~
  > let (x,w1) = action1 w0 in
- > let (y,w2) - action2 w1 in
+ > let (y,w2) = action2 w1 in
  > ~~~
  > 
  > and
@@ -2756,9 +2753,9 @@ Haskell has made a syntactical sugar for us:
 
 <code class="haskell">
 do
-  y <- action1
+  x <- action1
-  z <- action2
+  y <- action2
-  t <- action3
+  z <- action3
   ...
 </code>
 
@@ -2782,7 +2779,8 @@ blindBind action1 action2 w0 =
     bind action (\_ -> action2) w0
 </code>
 
-I didn't curried this definition for clarity purpose. Of course we can use a better notation, we'll use the `(>>)` operator.
+I didn't simplified this definition for clarity purpose.
+Of course we can use a better notation, we'll use the `(>>)` operator.
 
 And
 

content/html/fr/blog/Haskell-the-Hard-Way.md

@@ -232,11 +232,6 @@ A major part of this tutorial will explain why.
 In Haskell, there is a `main` function and every object has a type.
 The type of `main` is `IO ()`.
 This means, `main` will cause side effects.
-`IO` is a ... . 
-Wait! No! I won't say it now!
-I am afraid to terrify you.
-You might run away crying.
-For now, I won't talk about what `IO` really is.
 
 Just remember that Haskell can look a lot like other imperative languages.
 
@@ -708,7 +703,7 @@ square'' x = (^2) x
 </code>
 </div>
 We can remove `x` in the left and right side!
-It's called currying.
+It's called η-reduction.
 
 <div class="codehighlight">
 <code class="haskell">
@@ -818,7 +813,7 @@ int evenSum(int *list) {
 int accumSum(int n, int *list) {
     int x;
     int *xs;
-    if (*list == NULL) { // if the list is empty
+    if (*list == 0) { // if the list is empty
         return n;
     } else {
         x = list[0]; // let x be the first element of the list
@@ -996,7 +991,9 @@ evenSum l = accumSum 0 l
 </code>
 </div>
 What is pattern matching? 
-Use value instead of general parameter name.
+Use value instead of general parameter name[^021301].
+
+[^021301]: For the brave, a more complete explanation of pattern matching can be found [here](http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html).
 
 Instead of saying: `foo l = if l == [] then <x> else <y>`
 You simply state:  
@@ -1042,7 +1039,7 @@ main = print $ evenSum [1..10]
 
 <hr/><a href="code/02_Hard_Part/14_Functions.lhs" class="cut">02_Hard_Part/<strong>14_Functions.lhs</strong></a>
 
-In Haskell you can simplify function definition by curry them.
+In Haskell you can simplify function definition by η-reducing them.
 For example,  instead of writing:
 
 <code class="haskell">
@@ -1227,7 +1224,7 @@ The `(.)` function correspond to the mathematical composition.
 (f . g . h) x ⇔  f ( g (h x))
 </code>
 
-We can take advantage of this operator to curry a bit more our function:
+We can take advantage of this operator to η-reduce our function:
 
 <code class="haskell">
 -- Version 9
@@ -2591,7 +2588,7 @@ let (y,w') = action x w in
 
 Even if for some line the first `x` argument isn't needed.
 The output type is a couple, `(answer, newWorldValue)`.
-Each function `f` must have a type of kind:
+Each function `f` must have a type similar to:
 
 <code class="haskell">
 f :: World -> (a,World)
@@ -2625,7 +2622,7 @@ And of course `actionN w :: (World) -> (a,World)`.
  > 
  > ~~~
  > let (x,w1) = action1 w0 in
- > let (y,w2) - action2 w1 in
+ > let (y,w2) = action2 w1 in
  > ~~~
  > 
  > and
@@ -2762,9 +2759,9 @@ Haskell has made a syntactical sugar for us:
 
 <code class="haskell">
 do
-  y <- action1
+  x <- action1
-  z <- action2
+  y <- action2
-  t <- action3
+  z <- action3
   ...
 </code>
 
@@ -2788,7 +2785,8 @@ blindBind action1 action2 w0 =
     bind action (\_ -> action2) w0
 </code>
 
-I didn't curried this definition for clarity purpose. Of course we can use a better notation, we'll use the `(>>)` operator.
+I didn't simplified this definition for clarity purpose.
+Of course we can use a better notation, we'll use the `(>>)` operator.
 
 And
 

multi/blog/Haskell-the-Hard-Way.md

@@ -285,11 +285,6 @@ A major part of this tutorial will explain why.
 In Haskell, there is a `main` function and every object has a type.
 The type of `main` is `IO ()`.
 This means, `main` will cause side effects.
-`IO` is a ... . 
-Wait! No! I won't say it now!
-I am afraid to terrify you.
-You might run away crying.
-For now, I won't talk about what `IO` really is.
 
 Just remember that Haskell can look a lot like other imperative languages.
 
@@ -761,7 +756,7 @@ square'' x = (^2) x
 </code>
 </div>
 We can remove `x` in the left and right side!
-It's called currying.
+It's called η-reduction.
 
 <div class="codehighlight">
 <code class="haskell">
@@ -871,7 +866,7 @@ int evenSum(int *list) {
 int accumSum(int n, int *list) {
     int x;
     int *xs;
-    if (*list == NULL) { // if the list is empty
+    if (*list == 0) { // if the list is empty
         return n;
     } else {
         x = list[0]; // let x be the first element of the list
@@ -1049,7 +1044,9 @@ evenSum l = accumSum 0 l
 </code>
 </div>
 What is pattern matching? 
-Use value instead of general parameter name.
+Use value instead of general parameter name[^021301].
+
+[^021301]: For the brave, a more complete explanation of pattern matching can be found [here](http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html).
 
 Instead of saying: `foo l = if l == [] then <x> else <y>`
 You simply state:  
@@ -1095,7 +1092,7 @@ main = print $ evenSum [1..10]
 
 <hr/><a href="code/02_Hard_Part/14_Functions.lhs" class="cut">02_Hard_Part/<strong>14_Functions.lhs</strong></a>
 
-In Haskell you can simplify function definition by curry them.
+In Haskell you can simplify function definition by η-reducing them.
 For example,  instead of writing:
 
 <code class="haskell">
@@ -1280,7 +1277,7 @@ The `(.)` function correspond to the mathematical composition.
 (f . g . h) x ⇔  f ( g (h x))
 </code>
 
-We can take advantage of this operator to curry a bit more our function:
+We can take advantage of this operator to η-reduce our function:
 
 <code class="haskell">
 -- Version 9
@@ -2644,7 +2641,7 @@ let (y,w') = action x w in
 
 Even if for some line the first `x` argument isn't needed.
 The output type is a couple, `(answer, newWorldValue)`.
-Each function `f` must have a type of kind:
+Each function `f` must have a type similar to:
 
 <code class="haskell">
 f :: World -> (a,World)
@@ -2678,7 +2675,7 @@ And of course `actionN w :: (World) -> (a,World)`.
  > 
  > ~~~
  > let (x,w1) = action1 w0 in
- > let (y,w2) - action2 w1 in
+ > let (y,w2) = action2 w1 in
  > ~~~
  > 
  > and
@@ -2815,9 +2812,9 @@ Haskell has made a syntactical sugar for us:
 
 <code class="haskell">
 do
-  y <- action1
+  x <- action1
-  z <- action2
+  y <- action2
-  t <- action3
+  z <- action3
   ...
 </code>
 
@@ -2841,7 +2838,8 @@ blindBind action1 action2 w0 =
     bind action (\_ -> action2) w0
 </code>
 
-I didn't curried this definition for clarity purpose. Of course we can use a better notation, we'll use the `(>>)` operator.
+I didn't simplified this definition for clarity purpose.
+Of course we can use a better notation, we'll use the `(>>)` operator.
 
 And
 

output/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/10_hello_you.lhs

@@ -40,10 +40,5 @@ A major part of this tutorial will explain why.
 In Haskell, there is a `main` function and every object has a type.
 The type of `main` is `IO ()`.
 This means, `main` will cause side effects.
-`IO` is a ... . 
-Wait! No! I won't say it now!
-I am afraid to terrify you.
-You might run away crying.
-For now, I won't talk about what `IO` really is.
 
 Just remember that Haskell can look a lot like other imperative languages.

output/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/20_Essential_Haskell/10a_Functions.lhs

@@ -30,7 +30,7 @@ You just have to put it inside parenthesis.
 > square'' x = (^2) x
 
 We can remove `x` in the left and right side!
-It's called currying.
+It's called η-reduction.
 
 > square''' = (^2)
 

output/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/10_Functions.lhs

@@ -53,7 +53,7 @@ int evenSum(int *list) {
 int accumSum(int n, int *list) {
     int x;
     int *xs;
-    if (*list == NULL) { // if the list is empty
+    if (*list == 0) { // if the list is empty
         return n;
     } else {
         x = list[0]; // let x be the first element of the list

output/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/13_Functions.lhs

@@ -10,7 +10,9 @@ Next, we can use pattern matching.
 >                 else accumSum n xs
 
 What is pattern matching? 
-Use value instead of general parameter name.
+Use value instead of general parameter name[^021301].
+
+[^021301]: For the brave, a more complete explanation of pattern matching can be found [here](http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html).
 
 Instead of saying: `foo l = if l == [] then <x> else <y>`
 You simply state:  

output/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/14_Functions.lhs

@@ -1,4 +1,4 @@
-In Haskell you can simplify function definition by curry them.
+In Haskell you can simplify function definition by η-reducing them.
 For example,  instead of writing:
 
 <code class="haskell">

output/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/16_Functions.lhs

@@ -31,7 +31,7 @@ The `(.)` function correspond to the mathematical composition.
 (f . g . h) x ⇔  f ( g (h x))
 </code>
 
-We can take advantage of this operator to curry a bit more our function:
+We can take advantage of this operator to η-reduce our function:
 
 <code class="haskell">
 -- Version 9

output/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/20_Detailled_IO.lhs

@@ -193,7 +193,7 @@ let (y,w') = action x w in
 
 Even if for some line the first `x` argument isn't needed.
 The output type is a couple, `(answer, newWorldValue)`.
-Each function `f` must have a type of kind:
+Each function `f` must have a type similar to:
 
 <code class="haskell">
 f :: World -> (a,World)
@@ -227,7 +227,7 @@ And of course `actionN w :: (World) -> (a,World)`.
  > 
  > ~~~
  > let (x,w1) = action1 w0 in
- > let (y,w2) - action2 w1 in
+ > let (y,w2) = action2 w1 in
  > ~~~
  > 
  > and
@@ -365,9 +365,9 @@ Haskell has made a syntactical sugar for us:
 
 <code class="haskell">
 do
-  y <- action1
+  x <- action1
-  z <- action2
+  y <- action2
-  t <- action3
+  z <- action3
   ...
 </code>
 
@@ -391,7 +391,8 @@ blindBind action1 action2 w0 =
     bind action (\_ -> action2) w0
 </code>
 
-I didn't curried this definition for clarity purpose. Of course we can use a better notation, we'll use the `(>>)` operator.
+I didn't simplified this definition for clarity purpose.
+Of course we can use a better notation, we'll use the `(>>)` operator.
 
 And
 

output/Scratch/en/blog/Haskell-the-Hard-Way/index.html

@@ -331,12 +331,7 @@ A major part of this tutorial will explain why.</p>
 
 <p>In Haskell, there is a <code>main</code> function and every object has a type.
 The type of <code>main</code> is <code>IO ()</code>.
-This means, <code>main</code> will cause side effects.
+This means, <code>main</code> will cause side effects.</p>
-<code>IO</code> is a &hellip; . 
-Wait! No! I won&rsquo;t say it now!
-I am afraid to terrify you.
-You might run away crying.
-For now, I won&rsquo;t talk about what <code>IO</code> really is.</p>
 
 <p>Just remember that Haskell can look a lot like other imperative languages.</p>
 
@@ -828,7 +823,7 @@ square'' x = (^2) x
 </pre>
 </div>
 <p>We can remove <code>x</code> in the left and right side!
-It&rsquo;s called currying.</p>
+It&rsquo;s called η-reduction.</p>
 
 <div class="codehighlight">
 <pre class="twilight">
@@ -946,7 +941,7 @@ Note, for simplicity, I assume the int list should end with the first <code>0</c
 <span class="Storage">int</span> <span class="Entity">accumS<span class="Entity">um</span></span>(<span class="Storage">int</span> n, <span class="Storage">int</span> *list) {
     <span class="Storage">int</span> x;
     <span class="Storage">int</span> *xs;
-    <span class="Keyword">if</span> (*list == <span class="Constant">NULL</span>) { <span class="Comment"><span class="Comment">//</span> if the list is empty</span>
+    <span class="Keyword">if</span> (*list == <span class="Constant">0</span>) { <span class="Comment"><span class="Comment">//</span> if the list is empty</span>
         <span class="Keyword">return</span> n;
     } <span class="Keyword">else</span> {
         x = list[<span class="Constant">0</span>]; <span class="Comment"><span class="Comment">//</span> let x be the first element of the list</span>
@@ -1125,7 +1120,7 @@ evenSum l = accumSum 0 l
 </pre>
 </div>
 <p>What is pattern matching? 
-Use value instead of general parameter name.</p>
+Use value instead of general parameter name<sup id="fnref:021301"><a href="#fn:021301" rel="footnote">3</a></sup>.</p>
 
 <p>Instead of saying: <code>foo l = if l == [] then &lt;x&gt; else &lt;y&gt;</code>
 You simply state:  </p>
@@ -1172,7 +1167,7 @@ main = <span class="Entity">print</span> $ evenSum [1..10]
 <hr />
 <p><a href="code/02_Hard_Part/14_Functions.lhs" class="cut">02_Hard_Part/<strong>14_Functions.lhs</strong></a></p>
 
-<p>In Haskell you can simplify function definition by curry them.
+<p>In Haskell you can simplify function definition by η-reducing them.
 For example,  instead of writing:</p>
 
 <pre class="twilight">
@@ -1359,7 +1354,7 @@ The <code>(.)</code> function correspond to the mathematical composition.</p>
 (f . g . h) x ⇔  f ( g (h x))
 </pre>
 
-<p>We can take advantage of this operator to curry a bit more our function:</p>
+<p>We can take advantage of this operator to η-reduce our function:</p>
 
 <pre class="twilight">
 <span class="Comment"><span class="Comment">--</span> Version 9</span>
@@ -1401,7 +1396,7 @@ squareEvenSum' = evenSum . (<span class="Entity">map</span> (^2))
 squareEvenSum'' = <span class="Entity">sum</span>' . (<span class="Entity">map</span> (^2)) . (<span class="Entity">filter</span> <span class="Entity">even</span>)
 </pre>
 </div>
-<p>We just had to add another &ldquo;transformation function&rdquo;<sup id="fnref:0216"><a href="#fn:0216" rel="footnote">3</a></sup>.</p>
+<p>We just had to add another &ldquo;transformation function&rdquo;<sup id="fnref:0216"><a href="#fn:0216" rel="footnote">4</a></sup>.</p>
 
 <pre><code>map (^2) [1,2,3,4] ⇔ [1,4,9,16]
 </code></pre>
@@ -2407,7 +2402,7 @@ Its definition is:</p>
 <p>This is a nice way to tell there was an error while trying to create/compute
 a value.
 The <code>maybeRead</code> function is a great example of this. 
-This is a function similar to the function <code>read</code><sup id="fnref:1"><a href="#fn:1" rel="footnote">4</a></sup>,
+This is a function similar to the function <code>read</code><sup id="fnref:1"><a href="#fn:1" rel="footnote">5</a></sup>,
 but if something goes wrong the returned value is <code>Nothing</code>.
 If the value is right, it returns <code>Just &lt;the value&gt;</code>.
 Don&rsquo;t try to understand too much of this function. 
@@ -2640,10 +2635,10 @@ It&rsquo;s type is then something like:</p>
 
 <p>Not all function could have access to this variable.
 Those who have access to this variable can potentially be impure.
-Functions whose the world variable isn&rsquo;t provided to should be pure<sup id="fnref:032001"><a href="#fn:032001" rel="footnote">5</a></sup>.</p>
+Functions whose the world variable isn&rsquo;t provided to should be pure<sup id="fnref:032001"><a href="#fn:032001" rel="footnote">6</a></sup>.</p>
 
 <p>Haskell consider the state of the world is an input variable for <code>main</code>.
-But the real type of main is closer to this one<sup id="fnref:032002"><a href="#fn:032002" rel="footnote">6</a></sup>:</p>
+But the real type of main is closer to this one<sup id="fnref:032002"><a href="#fn:032002" rel="footnote">7</a></sup>:</p>
 
 <pre class="twilight">
 <span class="Entity">main</span> :: <span class="Constant">World</span> -&gt; ((),<span class="Constant">World</span>)
@@ -2743,7 +2738,7 @@ Each line is of the form:</p>
 
 <p>Even if for some line the first <code>x</code> argument isn&rsquo;t needed.
 The output type is a couple, <code>(answer, newWorldValue)</code>.
-Each function <code>f</code> must have a type of kind:</p>
+Each function <code>f</code> must have a type similar to:</p>
 
 <pre class="twilight">
 <span class="Entity">f</span> :: <span class="Constant">World</span> -&gt; (<span class="Variable">a,World</span>)
@@ -2777,7 +2772,7 @@ And in particular, each action can take a parameter from the result of a line ab
   <p>IMPORTANT, there are only two important pattern for us:</p>
 
   <pre><code>let (x,w1) = action1 w0 in
-let (y,w2) - action2 w1 in
+let (y,w2) = action2 w1 in
 </code></pre>
 
   <p>and</p>
@@ -2914,9 +2909,9 @@ Haskell has made a syntactical sugar for us:</p>
 
 <pre class="twilight">
 <span class="Keyword">do</span>
-  y &lt;- action1
+  x &lt;- action1
-  z &lt;- action2
+  y &lt;- action2
-  t &lt;- action3
+  z &lt;- action3
   ...
 </pre>
 
@@ -2940,7 +2935,8 @@ blindBind action1 action2 w0 =
     bind action (\_ -&gt; action2) w0
 </pre>
 
-<p>I didn&rsquo;t curried this definition for clarity purpose. Of course we can use a better notation, we&rsquo;ll use the <code>(&gt;&gt;)</code> operator.</p>
+<p>I didn&rsquo;t simplified this definition for clarity purpose.
+Of course we can use a better notation, we&rsquo;ll use the <code>(&gt;&gt;)</code> operator.</p>
 
 <p>And</p>
 
@@ -3271,7 +3267,7 @@ In particular, monad are very useful for: </p>
 </ul>
 
 <p>If you have followed me until here, then you&rsquo;ve done it! 
-You know monads<sup id="fnref:03021301"><a href="#fn:03021301" rel="footnote">7</a></sup>!</p>
+You know monads<sup id="fnref:03021301"><a href="#fn:03021301" rel="footnote">8</a></sup>!</p>
 
 <p><a href="code/03_Hell/02_Monads/13_Monads.lhs" class="cut">03_Hell/02_Monads/<strong>13_Monads.lhs</strong> </a></p>
 
@@ -3628,6 +3624,9 @@ treeFromList' (x:xs) n = <span class="Constant">Node</span> x left right
     <li id="fn:2">
       <p>I know I cheat. But I will talk about non-strict later.<a href="#fnref:2" rel="reference">&#8617;</a></p>
     </li>
+    <li id="fn:021301">
+      <p>For the brave, a more complete explanation of pattern matching can be found <a href="http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html">here</a>.<a href="#fnref:021301" rel="reference">&#8617;</a></p>
+    </li>
     <li id="fn:0216">
       <p>You should remark <code>squareEvenSum''</code> is more efficient that the two other versions. The order of <code>(.)</code> is important.<a href="#fnref:0216" rel="reference">&#8617;</a></p>
     </li>

output/Scratch/fr/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/10_hello_you.lhs

@@ -40,10 +40,5 @@ A major part of this tutorial will explain why.
 In Haskell, there is a `main` function and every object has a type.
 The type of `main` is `IO ()`.
 This means, `main` will cause side effects.
-`IO` is a ... . 
-Wait! No! I won't say it now!
-I am afraid to terrify you.
-You might run away crying.
-For now, I won't talk about what `IO` really is.
 
 Just remember that Haskell can look a lot like other imperative languages.

output/Scratch/fr/blog/Haskell-the-Hard-Way/code/01_basic/20_Essential_Haskell/10a_Functions.lhs

@@ -30,7 +30,7 @@ You just have to put it inside parenthesis.
 > square'' x = (^2) x
 
 We can remove `x` in the left and right side!
-It's called currying.
+It's called η-reduction.
 
 > square''' = (^2)
 

output/Scratch/fr/blog/Haskell-the-Hard-Way/code/02_Hard_Part/10_Functions.lhs

@@ -53,7 +53,7 @@ int evenSum(int *list) {
 int accumSum(int n, int *list) {
     int x;
     int *xs;
-    if (*list == NULL) { // if the list is empty
+    if (*list == 0) { // if the list is empty
         return n;
     } else {
         x = list[0]; // let x be the first element of the list

output/Scratch/fr/blog/Haskell-the-Hard-Way/code/02_Hard_Part/13_Functions.lhs

@@ -10,7 +10,9 @@ Next, we can use pattern matching.
 >                 else accumSum n xs
 
 What is pattern matching? 
-Use value instead of general parameter name.
+Use value instead of general parameter name[^021301].
+
+[^021301]: For the brave, a more complete explanation of pattern matching can be found [here](http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html).
 
 Instead of saying: `foo l = if l == [] then <x> else <y>`
 You simply state:  

output/Scratch/fr/blog/Haskell-the-Hard-Way/code/02_Hard_Part/14_Functions.lhs

@@ -1,4 +1,4 @@
-In Haskell you can simplify function definition by curry them.
+In Haskell you can simplify function definition by η-reducing them.
 For example,  instead of writing:
 
 <code class="haskell">

output/Scratch/fr/blog/Haskell-the-Hard-Way/code/02_Hard_Part/16_Functions.lhs

@@ -31,7 +31,7 @@ The `(.)` function correspond to the mathematical composition.
 (f . g . h) x ⇔  f ( g (h x))
 </code>
 
-We can take advantage of this operator to curry a bit more our function:
+We can take advantage of this operator to η-reduce our function:
 
 <code class="haskell">
 -- Version 9

output/Scratch/fr/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/20_Detailled_IO.lhs

@@ -193,7 +193,7 @@ let (y,w') = action x w in
 
 Even if for some line the first `x` argument isn't needed.
 The output type is a couple, `(answer, newWorldValue)`.
-Each function `f` must have a type of kind:
+Each function `f` must have a type similar to:
 
 <code class="haskell">
 f :: World -> (a,World)
@@ -227,7 +227,7 @@ And of course `actionN w :: (World) -> (a,World)`.
  > 
  > ~~~
  > let (x,w1) = action1 w0 in
- > let (y,w2) - action2 w1 in
+ > let (y,w2) = action2 w1 in
  > ~~~
  > 
  > and
@@ -365,9 +365,9 @@ Haskell has made a syntactical sugar for us:
 
 <code class="haskell">
 do
-  y <- action1
+  x <- action1
-  z <- action2
+  y <- action2
-  t <- action3
+  z <- action3
   ...
 </code>
 
@@ -391,7 +391,8 @@ blindBind action1 action2 w0 =
     bind action (\_ -> action2) w0
 </code>
 
-I didn't curried this definition for clarity purpose. Of course we can use a better notation, we'll use the `(>>)` operator.
+I didn't simplified this definition for clarity purpose.
+Of course we can use a better notation, we'll use the `(>>)` operator.
 
 And
 

output/Scratch/fr/blog/Haskell-the-Hard-Way/index.html

@@ -338,12 +338,7 @@ A major part of this tutorial will explain why.</p>
 
 <p>In Haskell, there is a <code>main</code> function and every object has a type.
 The type of <code>main</code> is <code>IO ()</code>.
-This means, <code>main</code> will cause side effects.
+This means, <code>main</code> will cause side effects.</p>
-<code>IO</code> is a &hellip; . 
-Wait! No! I won&rsquo;t say it now!
-I am afraid to terrify you.
-You might run away crying.
-For now, I won&rsquo;t talk about what <code>IO</code> really is.</p>
 
 <p>Just remember that Haskell can look a lot like other imperative languages.</p>
 
@@ -835,7 +830,7 @@ square'' x = (^2) x
 </pre>
 </div>
 <p>We can remove <code>x</code> in the left and right side!
-It&rsquo;s called currying.</p>
+It&rsquo;s called η-reduction.</p>
 
 <div class="codehighlight">
 <pre class="twilight">
@@ -953,7 +948,7 @@ Note, for simplicity, I assume the int list should end with the first <code>0</c
 <span class="Storage">int</span> <span class="Entity">accumS<span class="Entity">um</span></span>(<span class="Storage">int</span> n, <span class="Storage">int</span> *list) {
     <span class="Storage">int</span> x;
     <span class="Storage">int</span> *xs;
-    <span class="Keyword">if</span> (*list == <span class="Constant">NULL</span>) { <span class="Comment"><span class="Comment">//</span> if the list is empty</span>
+    <span class="Keyword">if</span> (*list == <span class="Constant">0</span>) { <span class="Comment"><span class="Comment">//</span> if the list is empty</span>
         <span class="Keyword">return</span> n;
     } <span class="Keyword">else</span> {
         x = list[<span class="Constant">0</span>]; <span class="Comment"><span class="Comment">//</span> let x be the first element of the list</span>
@@ -1132,7 +1127,7 @@ evenSum l = accumSum 0 l
 </pre>
 </div>
 <p>What is pattern matching? 
-Use value instead of general parameter name.</p>
+Use value instead of general parameter name<sup id="fnref:021301"><a href="#fn:021301" rel="footnote">3</a></sup>.</p>
 
 <p>Instead of saying: <code>foo l = if l == [] then &lt;x&gt; else &lt;y&gt;</code>
 You simply state:  </p>
@@ -1179,7 +1174,7 @@ main = <span class="Entity">print</span> $ evenSum [1..10]
 <hr />
 <p><a href="code/02_Hard_Part/14_Functions.lhs" class="cut">02_Hard_Part/<strong>14_Functions.lhs</strong></a></p>
 
-<p>In Haskell you can simplify function definition by curry them.
+<p>In Haskell you can simplify function definition by η-reducing them.
 For example,  instead of writing:</p>
 
 <pre class="twilight">
@@ -1366,7 +1361,7 @@ The <code>(.)</code> function correspond to the mathematical composition.</p>
 (f . g . h) x ⇔  f ( g (h x))
 </pre>
 
-<p>We can take advantage of this operator to curry a bit more our function:</p>
+<p>We can take advantage of this operator to η-reduce our function:</p>
 
 <pre class="twilight">
 <span class="Comment"><span class="Comment">--</span> Version 9</span>
@@ -1408,7 +1403,7 @@ squareEvenSum' = evenSum . (<span class="Entity">map</span> (^2))
 squareEvenSum'' = <span class="Entity">sum</span>' . (<span class="Entity">map</span> (^2)) . (<span class="Entity">filter</span> <span class="Entity">even</span>)
 </pre>
 </div>
-<p>We just had to add another &ldquo;transformation function&rdquo;<sup id="fnref:0216"><a href="#fn:0216" rel="footnote">3</a></sup>.</p>
+<p>We just had to add another &ldquo;transformation function&rdquo;<sup id="fnref:0216"><a href="#fn:0216" rel="footnote">4</a></sup>.</p>
 
 <pre><code>map (^2) [1,2,3,4] ⇔ [1,4,9,16]
 </code></pre>
@@ -2414,7 +2409,7 @@ Its definition is:</p>
 <p>This is a nice way to tell there was an error while trying to create/compute
 a value.
 The <code>maybeRead</code> function is a great example of this. 
-This is a function similar to the function <code>read</code><sup id="fnref:1"><a href="#fn:1" rel="footnote">4</a></sup>,
+This is a function similar to the function <code>read</code><sup id="fnref:1"><a href="#fn:1" rel="footnote">5</a></sup>,
 but if something goes wrong the returned value is <code>Nothing</code>.
 If the value is right, it returns <code>Just &lt;the value&gt;</code>.
 Don&rsquo;t try to understand too much of this function. 
@@ -2647,10 +2642,10 @@ It&rsquo;s type is then something like:</p>
 
 <p>Not all function could have access to this variable.
 Those who have access to this variable can potentially be impure.
-Functions whose the world variable isn&rsquo;t provided to should be pure<sup id="fnref:032001"><a href="#fn:032001" rel="footnote">5</a></sup>.</p>
+Functions whose the world variable isn&rsquo;t provided to should be pure<sup id="fnref:032001"><a href="#fn:032001" rel="footnote">6</a></sup>.</p>
 
 <p>Haskell consider the state of the world is an input variable for <code>main</code>.
-But the real type of main is closer to this one<sup id="fnref:032002"><a href="#fn:032002" rel="footnote">6</a></sup>:</p>
+But the real type of main is closer to this one<sup id="fnref:032002"><a href="#fn:032002" rel="footnote">7</a></sup>:</p>
 
 <pre class="twilight">
 <span class="Entity">main</span> :: <span class="Constant">World</span> -&gt; ((),<span class="Constant">World</span>)
@@ -2750,7 +2745,7 @@ Each line is of the form:</p>
 
 <p>Even if for some line the first <code>x</code> argument isn&rsquo;t needed.
 The output type is a couple, <code>(answer, newWorldValue)</code>.
-Each function <code>f</code> must have a type of kind:</p>
+Each function <code>f</code> must have a type similar to:</p>
 
 <pre class="twilight">
 <span class="Entity">f</span> :: <span class="Constant">World</span> -&gt; (<span class="Variable">a,World</span>)
@@ -2784,7 +2779,7 @@ And in particular, each action can take a parameter from the result of a line ab
   <p>IMPORTANT, there are only two important pattern for us:</p>
 
   <pre><code>let (x,w1) = action1 w0 in
-let (y,w2) - action2 w1 in
+let (y,w2) = action2 w1 in
 </code></pre>
 
   <p>and</p>
@@ -2921,9 +2916,9 @@ Haskell has made a syntactical sugar for us:</p>
 
 <pre class="twilight">
 <span class="Keyword">do</span>
-  y &lt;- action1
+  x &lt;- action1
-  z &lt;- action2
+  y &lt;- action2
-  t &lt;- action3
+  z &lt;- action3
   ...
 </pre>
 
@@ -2947,7 +2942,8 @@ blindBind action1 action2 w0 =
     bind action (\_ -&gt; action2) w0
 </pre>
 
-<p>I didn&rsquo;t curried this definition for clarity purpose. Of course we can use a better notation, we&rsquo;ll use the <code>(&gt;&gt;)</code> operator.</p>
+<p>I didn&rsquo;t simplified this definition for clarity purpose.
+Of course we can use a better notation, we&rsquo;ll use the <code>(&gt;&gt;)</code> operator.</p>
 
 <p>And</p>
 
@@ -3278,7 +3274,7 @@ In particular, monad are very useful for: </p>
 </ul>
 
 <p>If you have followed me until here, then you&rsquo;ve done it! 
-You know monads<sup id="fnref:03021301"><a href="#fn:03021301" rel="footnote">7</a></sup>!</p>
+You know monads<sup id="fnref:03021301"><a href="#fn:03021301" rel="footnote">8</a></sup>!</p>
 
 <p><a href="code/03_Hell/02_Monads/13_Monads.lhs" class="cut">03_Hell/02_Monads/<strong>13_Monads.lhs</strong> </a></p>
 
@@ -3635,6 +3631,9 @@ treeFromList' (x:xs) n = <span class="Constant">Node</span> x left right
     <li id="fn:2">
       <p>I know I cheat. But I will talk about non-strict later.<a href="#fnref:2" rel="reference">&#8617;</a></p>
     </li>
+    <li id="fn:021301">
+      <p>For the brave, a more complete explanation of pattern matching can be found <a href="http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html">here</a>.<a href="#fnref:021301" rel="reference">&#8617;</a></p>
+    </li>
     <li id="fn:0216">
       <p>You should remark <code>squareEvenSum''</code> is more efficient that the two other versions. The order of <code>(.)</code> is important.<a href="#fnref:0216" rel="reference">&#8617;</a></p>
     </li>